[meteorite-list] Mars Exploration Rovers Update: June 27 - July 4, 2008

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 11 Jul 2008 18:20:29 -0700 (PDT)
Message-ID: <200807120120.SAA24948_at_zagami.jpl.nasa.gov>

http://marsrovers.jpl.nasa.gov/mission/status.html

SPIRIT UPDATE: Biding Time - sol 1594-1600, June 27-July 03, 2008:

Spirit continues to ride out the Martian winter by doing minimal
activities to conserve power. The rover conducts very light science
activities every three to four Martian days, or sols, and relays data to
NASA's Odyssey orbiter for transmission to Earth every 4 sols. The rest
of the time, Spirit mostly sleeps.

As it has been some time since Spirit's operators were able to
synchronize the spacecraft clock to Earth time, they wished to determine
how far the spacecraft clock had drifted (how much it had changed over
time). Synchronization of the clock is a process that requires a
power-intensive, two-way, X-band communications link. When the power
situation allowed it, they decided to perform an X-band "beep" (a
five-minute, low-gain communication session) to estimate the amount of
drift. The transmission of plans to do so on sol 1594 (June 27, 2008)
were not detected by the ground station. Engineers hoped to make another
attempt on sol 1604 (July 7, 2008).

Spirit is healthy and all subsystems were performing as expected as of
the Odyssey downlink on sol 1598 (July 1, 2008). Solar-array energy has
been steady within the range of 225 watt-hours to 230 watt-hours (100
watt-hours is the amount of energy needed to light a 100-watt bulb for
one hour).

Sol-by-sol summary

During the past week, Spirit completed the following activities:

Sol 1594 (June 27, 2008): Plans called for Spirit to perform a
five-minute "beep" at X-band frequencies after relaying data to Earth
via the Odyssey orbiter.

Sol 1595: Spirit recharged the battery and measured atmospheric dust
opacity, known as Tau, using the panoramic camera.

Sol 1596: Spirit recharged the battery and measured atmospheric dust
opacity with the panoramic camera.

Sol 1597: Spirit recharged the battery and measured atmospheric dust
opacity with the panoramic camera.

Sol 1598: Spirit received new instructions from Earth via the rover's
high-gain, X-band antenna and relayed data to Odyssey at UHF frequencies
for transmission of the latest Martian data to Earth. The rover measured
atmospheric darkness caused by suspended dust particles with the
panoramic camera.

Sol 1599: Spirit conducted light remote sensing.

Sol 1600 (July 3, 2008): Spirit recharged the battery and again measured
atmospheric dust with the panoramic camera.

Odometry:

As of sol 1598 (July 1, 2008), Spirit's total odometry remained at
7,528.0 meters (4.7 miles).

------------------------------------------------------------------------

OPPORTUNITY UPDATE: Rover Takes Photos of Scenic View - sol 1574-1580,
June 28-July 04, 2008:

Opportunity has completed work on the stand-off portion of the
full-color panorama of the layered cliff known as "Cape Verde." It may
take a couple of weeks for the entire panorama to arrive on Earth,
depending on the volume of data the rover is able to transmit during
communications links.

Next, Opportunity will move closer to Cape Verde to take a
high-resolution image of a smaller area in front of the rover.

During the past week, engineers characterized the performance of the
rover's rock abrasion tool along the z-axis by comparing voltage and the
speed of the actuator at different temperatures. In the event that the
z-axis encoder lines break, as have the encoder lines for the rotate and
revolve axes, this characterization will be essential in developing a
functional strategy for operating the rock abrasion tool with full,
open-loop control. The z-axis encoder is responsible for moving the
cutting head outward into the rock.

Next week's plans call for Opportunity to bump forward to a point only a
few meters away from the cliff face to take high-resolution images. If
possible, Opportunity will also conduct scientific studies of an outcrop
target called "Nevada" (so named because of a rock next to it which has
a shape reminiscent of the outline of the state of Nevada) using
instruments on the robotic arm.

Opportunity is healthy and all subsystems are performing as expected.
Energy is around 376 watt-hours (100 watt-hours is the amount of energy
required to light a 100-watt bulb for one hour). As of Sol 1578 (July 2,
2008), Tau (a measure of darkness due to atmospheric dust) was at 0.413
and the dust factor (a measure of the proportion of sunlight penetrating
dust on the solar arrays) was at 0.771.

Sol-by-sol summary:

In addition to receiving morning, direct-from-Earth instructions via the
rover's high-gain antenna, sending evening UHF data to NASA's Odyssey
orbiter for transmission to Earth, measuring atmospheric dust with the
panoramic camera, surveying the sky for clouds with the navigation
camera, and monitoring dust accumulation on the rover mast, Opportunity
completed the following activities:

Sol 1574 (June 28, 2008): Opportunity began acquiring "dusty,"
super-resolution images of targeted portions of the outcrops exposed in
the Cape Verde cliff dubbed "Alpha," "Bravo," "Charlie," "Delta," and
"Echo." To do this, the rover compensated for dust accumulation on the
right side of each lens by taking images using only a subset of
available pixels. On this particular sol, Opportunity acquired dusty,
super-resolution images of "Alpha" and "Echo."

Sol 1575: Opportunity acquired dusty, super-resolution images of Bravo,
Charlie, Delta, and Echo using the panoramic camera. The rover also
acquired six, time-lapse movie frames in search of clouds using the
navigation camera.

Sol 1576: Opportunity acquired more dusty, super-resolution images of
Echo with the panoramic camera and took images of Cape Verde in shadow
at 2:30 p.m. local Mars time and at 3 p.m. local Mars time.

Sol 1577: Opportunity acquired dusty, super-resolution images of a
target dubbed "Foxtrot" with the panoramic camera and characterized the
performance of the rock-abrasion tool along the z-axis at warm
temperatures. The rover reacquired five dusty, super-resolution images
of Cape Verde and Bravo.

Sol 1578: Opportunity characterized the ability of the z-axis encoder to
move the cutting head of the rock abrasion tool outward at cold
temperatures and reacquired dusty, super-resolution images of Alpha.

Sol 1579: In the morning, Opportunity surveyed the horizon with the
panoramic camera. The rover measured argon gas in the Martian atmosphere
using the alpha-particle X-ray spectrometer. Opportunity also acquired a
27-by-1 panel of images of Cape Verde at dusk with the left-hand lens of
the panoramic camera.

Sol 1580 (July 4, 2008): Opportunity acquired a 27-by-1 panel of images
of Cape Verde at dusk with the right-hand lens of the panoramic camera.

Odometry:

As of sol 1580 (July 4, 2008), Opportunity's total odometry was
11,723.94 meters (7.28 miles).
Received on Fri 11 Jul 2008 09:20:29 PM PDT